New clinical problems have emerged for patients with thalassemia as their lifespan has been increased by improved transfusion therapy and the regular use of the iron chelating agent deferoxamine. Foremost among these problems are osteoporosis and an increased incidence of fractures. The present study has been designed to assess bone mineral density on a longitudinal basis as part of an ongoing comprehensive evaluation of endocrine disturbances in patients with thalassemia.